The present invention relates to an exhaust gas cleaning device for cleaning exhaust gases discharged from an internal combustion engine of an automobile or the like, particularly to an exhaust gas cleaning device provided with a filter member for collecting carbon particulates in exhaust gases discharged from a diesel engine and an electrically heating means for burning off the particulates collected by the filter member.
As the filter member to be employed in the exhaust gas cleaning device of this type, a honeycomb structured ceramic fiber member having a large number of gas inlet passages and a large number of gas outlet passages which are defined by a large number of intersecting porous walls so as to be adjacent to each other, has been proposed.
In this filter member, exhaust gases discharged from an internal combustion engine flow into the gas inlet passages, pass the porous walls and are discharged from the adjacent gas outlet passages. During the above process, carbon particulates are adhered to the surface of the porous walls defining the gas inlet passages.
As the carbon particulates are accumulated on the surface of the above porous walls, the flowing resistance of the filter member gradually increases. At last, the porous walls are clogged with the accumulated carbon particulates to reduce the output of the engine.
Therefore, it is required to regenerate the filter member by periodically eliminating carbon particulates accumulated on the surface of the porous walls.
As the filter member regenerating means, a heater wire made of nichrome wire or the like, which is provided within exhaust gas passages of the filter member or near the upstream end surface of the filter member for burning off collected particulates, has been proposed.
However, the heater wire is apt to be short-circuited with another heater wire or peeled from the filter member due to vibrations or the like of the automobile. Therefore, great care must be taken when the heater wire is mounted on the filter member.
Accordingly, an object of the present invention is to provide an exhaust gas cleaning device provided with an electric heater which can be integrally mounted on a filter member by a simple mounting structure without being peeled therefrom.